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Alpha Circini - HD128898 - HIP71908

Alpha Circini is a blue to white main sequence dwarf star that can be located in the constellation of Circinus. Alpha Circini is the Bayer Classification for the star. HIP71908 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD128898.

Location of Alpha Circini

The location of the star in the galaxy is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the star is compared to the celestial equator and is expressed in degrees. For Alpha Circini, the location is 14h 42m 30.69 and -64d58`28.5 .

Proper Motion of Alpha Circini

All stars like planets orbit round a central spot, in the case of planets, its the central star such as the Sun. In the case of a star, its the galactic centre. The constellations that we see today will be different than they were 50,000 years ago or 50,000 years from now. Proper Motion details the movements of these stars and are measured in milliarcseconds. The star is moving -233.51 ± 000.10 towards the north and -192.53 ± 000.14 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Alpha Circini

Alpha Circini has a spectral type of F1Vp. This means the star is a blue to white main sequence dwarf star. The star has a B-V Colour Index of 0.25 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 7,483 Kelvin.

Alpha Circini has been calculated as 2.10 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,462,903.32.km.

Alpha Circini Apparent and Absolute Magnitudes

Alpha Circini has an apparent magnitude of 3.18 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, you would get an absolute magnitude of 2.11 If you used the 2007 Parallax value, you would get an absolute magnitude of 2.08. Magnitude, whether it be apparent/visual or absolute magnitude is measured by a number, the smaller the number, the brighter the Star is. Our own Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Distance to Alpha Circini

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 60.97 which gave the calculated distance to Alpha Circini as 53.50 light years away from Earth or 16.40 parsecs. In 2007, Hipparcos data was revised with a new parallax of 60.35 which put Alpha Circini at a distance of 54.05 light years or 16.57 parsecs.

It would take a spaceship travelling at the speed of light, 53.50 years using the 1997 distance to get there. We don't have the technology or spaceship that can carry people over that distance yet.

Source of Information

The source of the information if it has a Hip I.D. is from Simbad, the Hipparcos data library based at the University at Strasbourg, France. Hipparcos was a E.S.A. satellite operation launched in 1989 for four years. The items in red are values that I've calculated so they could well be wrong. Information regarding Stellar Age, Metallicity or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

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Alpha Circini Facts

Alternative Names

Bayer DesignationAlpha Circini
Hipparcos Library I.D.71908
Henry Draper Designation128898

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude2.11 / 2.08
Apparent Magnitude3.18
Right Ascension (R.A.)14h 42m 30.69
Declination (Dec.)-64d58`28.5
1997 Distance from Earth60.97 Parallax (milliarcseconds)
 53.50 Light Years
 16.40 Parsecs
2007 Distance from Earth60.35 Parallax (milliarcseconds)
 54.05 Light Years
 16.57 Parsecs
Proper Motion Dec.-233.51 ± 0.10 milliarcseconds/year
Proper Motion RA.-192.53 ± 0.14 milliarcseconds/year
B-V Index0.25
Spectral TypeF1Vp
Colour(F) blue to white

Estimated Facts

Radius (x the Sun)2.10
Calculated Effective Temperature7,483 Kelvin

Sources and Links

SIMBAD SourceLink

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.


Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
128898-64 2977.4A3.40000-206.00000-244.00000A0White
B8.80000-188.00000-264.000001951

Location of Alpha Circini in Circinus


Alpha Circini (Alpha Circini) Location in Circinus

The map was generated using Night Vision, an awesome free application by Brian Simpson.



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